Recent advances in technology allow mobile devices to find their physical location via a multitude of methods: cell tower look up, cell tower triangulation, cell tower and Wi-Fi access point triangulation and Global Positioning System (GPS), with varying accuracy levels. Besides the use of location estimation for navigation services, a location-based service (LBS) is an information and entertainment service, accessible with mobile devices through the mobile network and utilizing the ability to make use of the geographical position of the mobile device. LBS services can be used in a variety of contexts, such as health, work, personal life, etc. LBS services include services to identify a location of a person or object, such as discovering the nearest banking cash machine or the whereabouts of a friend or employee. LBS services include parcel tracking and vehicle tracking services. LBS can include mobile commerce when taking the form of coupons or advertising directed at customers based on their current location. LBS can include personalized weather services and even location-based games.
A new class of LBS, referred to as “serendipitous” location-based services, have also gained popularity. These services and applications allow users to serendipitously, i.e., accidentally discover user, businesses and other locations around them that match their interests. A user can look up who else is in proximity and depending on common interests, can decide to communicate. Furthermore, location tagging services allow a user to leave interesting tags about a particular geographic location, e.g., photos or snippets about current events, etc., and then other users who are in vicinity of that location could be automatically prompted with those geo-tags. Finally, location-based advertising allows a retailer to send advertisements to users on detecting that a user, who previously opted-in to the service, has entered the “geo-fence” area around the retailer. The fundamental questions relevant to these serendipitous location-based services remain yet unanswered. For instance, how likely is it to meet in users' daily lives, and where, with user who share similar interests in cyber domain? What role does user's physical location play in terms of what they access online from there?